Windows 8 is just what Microsoft needs to take advantage of the ongoing irreversible shift from PCs to handheld devices including iPads, iPhones, and other form factors yet to be designed, according to the company's former OEM chief.

Windows 8 hasn't even been on sale for a month yet but is already the recipient of three critical security updates via Microsoft's monthly Patch Tuesday security bulletins, each of which will block flaws that allow remote execution of code on targeted machines.

Microsoft has set some ambitious goals for Windows 8—400 million devices in customer hands by next July and more than 100,000 applications stocked in the Windows Store by the end of January, according to a top Microsoft sales exec.

Windows 8 will help boost overall sales of tablets by nearly 10 million this year over estimates made just three months ago, but Android and Apple products will be the main driver behind the increase, according to IDC.